An indictment on chemo might seem harsh, but think of it this way, Klosterman says: Chemotherapy is essentially a process in which doctors pump poison into sick patients’ bodies. While the poison typically does kill harmful cancer cells, it isn’t specific enough to avoid killing healthy cells in the crossfire.

As a result, many cancer patients get sick while receiving treatment, lose their hair, and find that their energy and strength disappear.

“Right now, chemotherapy is the best cancer treatment therapy we have,” Klosterman says. “But let’s say we find some way where we can almost genetically engineer the DNA of our being and fight cancer that way. Then, the idea that we used to pump poison into people to fight off cancer will almost seem like the use of leeches or something.”

Fortunately for medical science in 2016, there is empirical evidence that chemotherapy works in certain cases. (The same can’t be said for leeching.)

People with leukemia, for example, tend to see a great deal of success when they use chemo, sometimes even to the point of a cure. Research suggests the typical survival rates range from 67% to 90%, depending on the patient’s age and genetic makeup. Other forms of cancer, including certain brain tumours, are totally immune to chemotherapy.

Chemo might not be completely comparable to leeching, but it can have some gruesome side effects.